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Intel's Atom processor unveiled

We dive into Silverthorne and the Menlow platform
— 12:05 AM on April 2, 2008

The trend toward ever smaller and cheaper PC components is, of course, nothing new. Chips have shrunk and prices have fallen for over 30 years now. Yet that trend has accelerated dramatically in recent years, spurred onward by the rise of mobile computing and signified by the success of low-cost laptops like the Asus Eee PC and high-zoot mobile computers like the iPhone. Sensing this trend, the world's largest chipmaker kicked off an effort four years ago to develop a CPU that could fit inside the power, heat, and size requirements of such devices while maintaining compatibility with its existing lineup of PC processors. Internally at Intel, this processor became known as Silverthorne, and the core logic associated with it was code-named Poulsbo. Together, they make up the so-called Menlow platform, whose development we've been tracking for some time now.

Today, Silverthorne and Menlow are taking their final shape with the introduction of the Intel Atom processor and the Centrino Atom mobile computing brand. Thanks to an all-new CPU microarchitecture and companion core-logic chip, Intel is pushing x86-compatible computing into new frontiers. To better understand how they did it, we recently visited the Austin, Texas offices of the Silverthorne design team and spoke with several of the chips' architects. Read on for an extensive overview of this new CPU and its related technology.

Thinking small—but not too small
One of the keys to understanding Silverthorne is understanding its place in the world. Intel designed Silverthorne to fit into thermal and physical footprints that none of its current processors could. In its initial incarnation, Silverthorne will consume between half a watt and two-and-a-half watts, much less than most x86-compatible processors. (The closest x86 competitor, VIA's Isaiah, will start at 3W and go up from there.) That power profile lets Silverthorne play in a number of different types of devices, including handheld GPS navigational devices and portable video players. Accordingly, Intel points to ARM processors as Silverthorne's primary competition.

However, Silverthorne's ability to fit into the smallest handheld devices, like smart phones, will be constrained in this first generation by the size and power consumption of its associated core-logic chip. Poulsbo was created to provide a fairly robust PC-style feature set for Ultra Mobile PCs and the like, with all of the necessary PC I/O interfaces and relatively powerful integrated graphics. The market failure of UMPCs and the triumph of the iPhone make Poulsbo's targets look like something of a miscalculation now. But Intel paints the Menlow platform as part of a planned progression to deliver PC compatibility and power into ever-smaller form factors over time. The next step in the process will be the product code-named Moorestown, due in the 2009-2010 time frame, that will incorporate a Silverthorne CPU core into a system-on-a-chip design that's better suited for smart phones.

Silverthorne and Poulsbo. Source: Intel.

In the interim, Intel will play to Silverthorne's strengths by aiming it at slightly larger devices in established product categories and by continuing to push for development of what it now calls mobile Internet devices, or MIDs. Chief among those strengths is Silverthorne's compatibility with Intel's other x86 processors, which Intel equates not just with PC compatibility but Internet compatibility, as well. The firm sees substantial opportunity for Silverthorne to win a place in the tens of millions of handheld GPS receivers, video and DVD players, and game machines that ship each year by endowing them with a standard instruction set. When combined with Wi-Fi connectivity, any such device could double as a capable web client and extend its functionality by grabbing data from the Internet for mash-ups and the like.

Part of Intel's strategy here is to make Silverthorne integration easy by fostering the development of a standard software stack that device makers can use to incorporate robust Internet client capabilities into their products with relative ease. To that end, Intel initiated the Mobile Linux Internet Project, or Moblin, online at, and says it has about 100 people working on Moblin development. Their efforts focus on a range of components, from the kernel to middleware to application and media handling frameworks, including codecs. Moblin is based on desktop Linux, but Intel worked to reduce the OS's footprint, to improve its power management features, and to standardize the APIs, so applications written for Moblin-based devices can work across different mobile Linux distros. Several OS vendors have signed on to package up Moblin into a complete product, among them Ubuntu and the Asianux consortium. More impressively, Intel cites a long list of application vendors and solution providers with Moblin-optimized products in the works, including Skype, Nero, AOL, MySpace, Adobe, Real, Dolby, and PopCap Games. With a slate of participants like that on deck, Moblin at least holds the promise of an even better web-client experience than Apple's iPhone. Moblin's project list includes a Mozilla-based web browser, as well, and its UI work includes provisions for touch-based navigation.

The choice of Linux over Windows may be a startling one coming from one of the members of the "Wintel" duo, but it makes sense to us. Linux has a smaller memory footprint, costs less (duh), and is more easily customizable than Windows. The user interfaces for MIDs and app-specific devices vary widely from one product to the next, so the familiarity of the Windows UI means little here. And, well, I've never been a terribly impressed with Windows Mobile, either.

Intel expects to showcase over 25 designs at the Atom's launch today. Presumably, some of those will be GPS receivers and the like, while others will be MID attempts. The Linux based ones will be smaller, lighter, and cheaper, starting at about $499 and going up from there. The Windows-based devices will be higher end products, starting at $599.

Obviously, with MIDs, Intel intends to help create a new category of products into which it can sell Silverthorne. Having seen the iPhone in action, however, I'm skeptical about the larger, bulkier MIDs' prospects for success. Because Silverthorne is such a small chip, it's also very cheap to produce, and Intel will be addressing other markets with this CPU, as well. The upcoming Diamondville platform will combine a Silverthorne processor with a different Intel chipset, and will target low-cost notebooks and desktops; it looks like a perfect fit for future generations of the Asus Eee PC and is already expected to be a part of the Eee PC desktop variant. Silverthorne will likely find its way into embedded applications, too. In both of these spaces, it will compete more directly with VIA's C7 and Isaiah processors.